With the exception of vehicles with fully or semi-automatic transmission, the drive and the shiftable transmission are separated by manual actuation of a clutch. For this purpose, the clutch is connected to a clutch pedal arranged in the vehicle interior and the clutch pedal is mounted pivotably on a pedal carrier.
The clutch cables used for force transmission are increasingly being replaced by hydraulic systems, which allow maintenance-free and, in particular, low-friction actuation. Hydraulic systems of this kind require a master cylinder connected to the clutch pedal. The clutch itself, on the other hand, has a slave cylinder, which is connected to the master cylinder for fluid transmission by a pressure line. The actuation of the clutch, which is thus hydraulic, is accomplished by appropriate modification of the pressure and/or volume flow of the hydraulic fluid contained in the hydraulic system.
The construction of a clutch pedal system of this kind envisages that the master cylinder, which is connected to the clutch pedal, is supported on the pedal carrier. The actual arrangement of the clutch pedal in the vehicle interior is accomplished by means of the pedal carrier.
The master cylinders are preferably standardized components with respect to, for example, the stroke and piston diameter thereof. This is essentially because identical parts are more economical to produce overall and easier to store as spare parts. However, vehicle-specific and model-dependent differences do not allow the use of master cylinders of identical construction. Thus, even differences in the inclination angle of the bulkhead and/or of the dashboard carrier contribute to the need for a redesign of the master cylinder. The underlying reason is that the alignment of the master cylinder relative to the clutch pedal changes with differences in the inclination angle, requiring a corresponding adaptation of the master cylinder. This is especially the case, given that the master cylinder and the hydraulic connections thereof must be in a definite position and/or orientation in order, for example, to enable bleeding of the hydraulic system.
In view of the increasing number of different master cylinder designs due to the increasing variety of models and vehicle-specific differences, it is completely impossible to achieve the preferred use of identical parts, or possible only with difficulty. This is disadvantageous, in particular, inasmuch as the hydraulic power of the master cylinder generally remains the same, despite the need for redesign. Given this situation, there is room for improvement in the design of clutch pedal systems and the master cylinders thereof in terms of an economical modular system.